it's no joke; gimme a break!
jokingly; in the form of a joke
seriously; no kidding; joking aside; in all seriousness
being somewhat (half) joking; half seriously; half in jest; in a jocular vein
(talking in a) half-joking manner
to crack a joke; to tell a joke
being somewhat (half) joking; half seriously; half in jest; in a jocular vein
to pass (something) off as a joke